INFI is well known to be a special smelt steel. Nathan the machinist has done some great head to head testing of INFI vs 3V and his own heat treat for 3V did quite well against INFI . The proof is out there you just need to look for it. Many people have used INFI to failure and found it to be what everyone says it is.
I worry that makes it sound like I'm trying to take on Infi with 3V in some sort of competitive way. I want to be very clear, I'm not.
All makers need examples of good quality standards to compare their work to in order to know where they are. If you're not able to accurately duplicate edge geometry and cut tests, you're not really ready to do this yet, but at some point you all need to accumulate samples of other known good work and start to quantify what edge retention and cutting performance really means. Infi is one of my standards, and it's a great standard because it has the gross edge durability that 3V often lacks. It is a gold standard for certain kinds of thing. I have nothing but respect for Jerry Busse and Infi steel because what he has been able to achieve with it. I have a Dozier D2 and a Cashen O1/L6 blend in there too. These are people who put a lot of work into getting it right, and it's helpful to study their work.
When you look at the steel performance comparison charts from places like Crucible you'll see things like "toughness" and wear resistance or edge holding or something, and for our application that's mostly a bunch of crap that could lead you to believe that something like S30V is super tough and has phenomenal edge retention. If a test is based on CATRA testing, a steel with lots of abrasion resistant vanadium carbide is going to do well. But in the real world people don't just sit there and lightly saw at abrasive card stock for hours at a time. In the real world, the ability of the matrix to support those carbides in a less-than-ideal cut is much more important.
Jerry Busse was right. For most people, their knives don't go dull from just abrasive wear. The edge deteriorates from either rolling or micro chipping just as much as abrasive or adhesive wear. So he optimized an alloy and a heat treat for toughness at both a gross level and at a microscopic level. Infi wears away abrasively, but you're hard pressed to dull it quickly from rough use.
3V has much better abrasive wear resistance, but that doesn't always translate into better edge retention because it can have that chippy mushy edge that the super steels often have. It can cut cardboard better than Infi, unless you're clacking against a hard cutting board at the end of the cut, and then Infi shines.
Those of use who have really optimized 3V have got it to equal the gross edge stability of Infi, which allows the better wear resistance of 3V to translate into better edge holding. But Infi will always have better gross toughness, so extremely rough use that is going to damage a knife will cause less damage to Infi.
In the final analysis, I think it is safe to say that both steels are very tough, with Infi the tougher of the two. And both steels have good edge retention, with 3V the better wearing of the two. Neither steel has great abrasive wear resistance and will dull in cardboard or leather faster than D2, but 3V is clearly the winner there. In my opinion, a knife that might see some rough or careless use either steel will perform much better than most of the other options out there. If you think you might need to chop a freakin boat anchor in half you should probably go with the Infi, and if you might need to cut a bunch of dirty and abrasive vegetation then you should probably go with 3V. They both perform very well in less-then-ideal situations. For my use, I get better results with 3V, but it is abundantly clear to me that plenty of people are well served with Infi.
